1. Field of the Invention
This invention relates to a fluid storage and gas dispensing system that may be utilized to store high pressure liquid or other fluid, for dispensing of gas from the system and use of the dispensed gas in an application such as the manufacture of semiconductor devices and materials.
2. Description of the Related Art
In a wide variety of industrial processes and applications, there is a need for a reliable source of process fluid(s).
For example, a safe, reliable and efficient fluid supply source is desirable in the field of semiconductor manufacturing, ion implantation, manufacture of flat panel displays, medical intervention and therapy, water treatment, emergency breathing equipment, welding operations, space-based delivery of liquids and gases, etc.
U.S. patent application Ser. No. 09/067,393 filed Apr. 28, 1998 in the names of Luping Wang and Glenn M. Tom describes a fluid storage and gas dispensing system including a storage and dispensing vessel for holding a fluid, e.g., a liquid at appropriate pressure whose vapor constitutes the fluid to be dispensed, or alternatively a compressed gas. The vessel includes an outlet port and is equipped with a dispensing assembly coupled to the outlet port, for example a valve head assembly including a dispensing valve and an outlet for selective discharge of gas deriving from liquid or compressed gas in the vessel.
In the Wang et al. system, a fluid pressure regulator is associated with the outlet port, and may be at least partially interiorly disposed in the vessel, optionally coupled with a phase separator assembly to prevent liquid from leaking to the dispensing valve and outlet when the fluid in the vessel is in the form of a liquefied gas. The fluid regulator preferably is fully interiorly disposed in the vessel, to minimize the possibility of impact and environmental exposure in use, and to minimize the leak path of the contained fluid from the vessel, so that a single weld or seam can be used at the outlet port, to seal the vessel.
The regulator is a flow control device, which can be set at a predetermined pressure level, to dispense gas or vapor from the cylinder at such pressure level. The pressure level set point may be super-atmospheric, sub-atmospheric or atmospheric pressure, depending on the dispensing conditions, and the mode of gas discharge from the vessel.
U.S. patent application Ser. No. 09/300,994 filed Apr. 28, 1999 in the names of Luping Wang and Glenn M. Tom for "FLUID STORAGE AND DISPENSING SYSTEM," is a continuation in part of the above-described U.S. patent application Ser. No. 09/067,393, and describes further aspects of the "regulator in a bottle" apparatus, including arrangements employing a double-stage (or multi-stage) fluid pressure regulator, optionally with a particulate filter assembly, interiorly disposed in the vessel. Such continuation in part application also discloses fluid storage and dispensing vessel arrangements in which the vessel encloses an interior volume of less than about 50 liters and has an inlet opening larger than 1 inch NGT, as well as embodiments in which the fluid storage and dispensing vessel contains a physical adsorbent material holding adsorbed gas at an internal pressure of from about 50 psig to about 5000 psig.
In the practice of the regulator in a bottle system of the above-discussed U.S. patent application Ser. No. 09/300,994 and U.S. patent application Ser. No. 09/067,393, there is a need for further improvement in certain aspects of the structure and operation of the fluid storage and dispensing system.
More specifically, when a set point regulator (SPR) is set at a predetermined pressure set point, and then interiorly disposed in the interior volume of the fluid storage and dispensing vessel of the system, the set point pressure is not thereafter adjustable during the use of the vessel.
This is disadvantageous, since the SPR is typically set for sub-atmospheric pressure release of gas, in order to maximize the safety of the fluid storage and dispensing system. Such sub-atmospheric pressure set point is advantageous during storage and transport of the vessel. In subsequent use, however, the pressure and fluid flow requirements of the gas-consuming process facility in which the fluid storage and dispensing system is used may dictate that fluid be dispensed at super-atmospheric pressure. For example, in a semiconductor manufacturing facility, the associated tool pressure may be &gt;760 Torr, or higher pressures otherwise may be necessary or desirable to achieve suitably high flow rates in the process facility. If the SPR is set at super-atmospheric pressure and then installed in the vessel, the safety of the fluid storage and dispensing system is compromised by the super-atmospheric pressure set point during transport and storage of the system, as well as during off-line (stand-by) periods in the process facility.
Another deficiency of the prior fluid storage and dispensing system is that it is not able to monitor pressure in the storage and dispensing vessel. As a result, it is difficult to determine or predict in advance when the vessel will be empty.
It would therefore be highly desirable, and is accordingly an object of the present invention, to provide a fluid storage and dispensing system that overcomes the aforementioned conflicting pressure level requirements between the storage/transport sub-atmospheric pressure levels desired for safety reasons on the one hand, and the super-atmospheric pressure operating levels desired in many applications on the other hand.
It is another object of the invention to provide a fluid storage and dispensing system comprising a storage and dispensing system with a regulator device interiorly positioned in the vessel, in which the amount of the fluid in the vessel is readily determinable.
It is another object of the invention to provide a fluid storage and dispensing system that allows for sub-atmospheric SPR set-point pressure during storage and transportation and super-atmospheric SPR set-point pressure during use.
It is another object of the invention to provide an improved fluid storage and dispensing system for the selective dispensing of gases, characterized by significant advantages in cost, ease of use, and performance.
Other objects and advantages of the invention will be more fully apparent from the ensuing disclosure and appended claims.